Mold-closing means, particularly for die-casting and injection molding machines for metals and synthetics

ABSTRACT

A mold-closing device, particularly for die-casting machines and injection-molding machines for metals and plastics, with a stationary mold-carrier plate mounted on columns, a stationary end plate, a mold-carrier plate movable between these stationary plates from a mold-open position to a mold-closed position, a pressure piece between the mold-carrier plate and the end plate, a pressure box or hydraulic intensifier mounted on the pressure piece for producing the closure pressure and for connecting the end plate with the movable mold-carrier plate only during the casting on injecting operation, at least two piston- andcylinder units acting between the movable mold-carrier and one of the stationary plates, and a thrust plate transversely slidable on the end plate so as to cover and uncover an aperture provided for the passage therethrough of the pressure piece, the pressure piece including a threaded sleeve or nut and a threaded spindle or ram.

United States Patent Cyriax [54] MOLD-CLOSING MEANS,

PARTICULARLY FOR DIE-CASTING AND INJECTION MOLDING MACHINES FOR METALS AND SYNTHETICS [72] Inventor: Wilhelm Cyriax, W.R. Neustadter Strasse 81, Kottingbrunn, Austria [22]. Filed: Jan. 8, 1970 [21] Appl. No.2 1,410

[30] Foreign Application Priority Data Jan. 13, 1969 Germany ..P 19 01 946.6

[ Aug. 29, 1972 567,063 9/1957 Italy ..18/30 LV 1,364,692 5/1964 France ..18/30 LV 912,866 12/1962 Great Britain ..18/30 LV 381,133 2/1963 Japan ..18/2 RP Primary ExaminerJ. Spencer Overholser Assistant Examiner-Michael 0. Sutton Attorney-Karl F. Ross [5 7] ABSTRACT A mold-closing device, particularly. for die-casting machines and injection-molding machines for metals and plastics, with a stationary mold-carrier plate mounted on columns, a stationary end plate, a moldcarrier plate movable between these stationary plates from a mold-open position to a mold-closed position, a pressure piece between the mold-carrier plate and the end plate, a pressure box or hydraulic intensifier mounted on the pressure piece for producing the closure pressure and for connecting the end plate with the movable mold-carrier plate only during the casting on injecting operation, at least two pistonandcylinder units acting between the movable mold-carrier and one of the stationary plates, and a thrust plate transversely slidable on the end plate so as to cover and uncover an aperture provided for the passage therethrough of the pressure piece, the pressure piece including a threaded sleeve or nut and a threaded spindle or ram.

1 Claim, 2 Drawing Figures PATENTED I972 3.687.590

sum 2 0r 2 gi BY W MOLD-CLOSING MEANS, PARTICULARLY FOR DIE-CASTING AND INJECTION MOLDING MACHINES FOR METALS AND SYNTHETICS FIELD OF THE INVENTION This invention relates to a mold-closing device, particularly for die-casting and injection-molding machines, for metals and plastics.

BACKGROUND OF THE INVENTION Mold-closing devices are known, which havea stationary mold-carrier plate accommodated upon crossbeams or columns, a stationary end plate likewise accommodated upon the cross-beams or columns, and a mold-carrier plate which is movable between these two plates from an open position into a closed position, and is guided upon the crossbeams or columns. The closing and opening movements of the mold are carried out with comparatively low pressures, while for the attainment of the requisite closing pressure between the movable mold-carrier plate and the end plate during the injection operation, a pressure piece equipped with a pressure box or hydraulic intensifier is provided; the pressure piece connects the stationary end plate with the movable mold-carrier plate only during the injection operation, so as to enable the mold to be opened for the release of the molded member.

In the interests of economical production and an economical operation of the machine, care must be taken, with these mold-closing devices, that the stationary end plate undergoes as little weakening as possible as a result of the aperture that is required for the passage of the pressure piece, in order that the use of excessively stout end plates may be obviated. A further requirement resides in the fact that the stroke of the movable mold-carrier plate must be adaptable to the size of the mold in each case.

With one known constructional form of this nature (German Federal Pat. No. 1,006,590), the pressure box of the pressure piece is accommodated upon the stationary end plate, separately from the press ram, in guiding rails, in order that it may be brought out of engagement with the press ram perpendicularly to the direction of motion of the mold-carrier plates. Closing cylinders are arranged laterally on the end plate and on the movable mold-carrier plate. The stationary moldcarrier plate has a diameter adapted to the diameter of the ram of the pressure box.

A serious disadvantage of this form of construction resides in the fact that the requisite adaptation of the stroke of the movable mold-carrier plate is effected by the pressure box, which must be available over a corresponding stroke. With this constructional form, therefore, the pressure box is saddled with the problem of bridging over, with a pressure piece of fixed length, the differences of length that are required owing to different opening widths of the mold. This renders a pressure box of great stroke volume necessary, with the result that the closing pressure, with an appropriate height of the mold, has to be transmitted by way a large column of pressure medium. In this case, however, on account of the compressibility of the pressure medium, a substantially greater quantity of pressure medium is needed than corresponds to the stroke volume.

Furthermore it is a disadvantage that the entire pressure box, which, on account of the massive structure required is of not inconsiderable weight, has to be moved in guides upon the end plate. These guides of the pressure box must be so constructed that in the operative position the axis of the pressure box coincides exactly with the axis of the ram of the pressure piece, since otherwise a canting of the pressure box would be the inevitable result. The cost of manufacture, including the shaping of the guides, is consequently very great.

Furthermore, structures have become known in which the mold-closing device is arranged in the end plate. With such a construction (DAS No. l, 231, 344) the mold-closing cylinder is accommodated between the crossbeams in the middle of the end plate. In order to adapt the stroke of the movable mold-carrier plate to the height of the mold, the end plate is adjustably arranged upon the four crossbeams. The disadvantage here resides in the fact that when adjusting the end plate, a uniform adjustment must be effected upon all four of the crossbeams, in order to ensure satisfactory operation. Moreover, the end plate is very complicated in its design or construction, and is very expensive to produce. In order to lock the closing cylinder (which carries at its end the movable mold-carrier plate) when the mold is closed, a bayonet-like hasp is provided on the end plate and this hasp, when the mold is closed, engages beneath the end of the cylinder, and becomes liberated, for the opening of the mold, after appropriate rotation.

In the case of a further construction (DAS No. 1,138,535), the cylinder is fixed in the end plate, and extends out beyond the end plate. The piston carries at its end the movable mold-carrier plate, equipped with a pressure box. A number of pressure pieces are, secured to the piston of the pressure box and these, when the mold is closed, bear against a perforated disc, rotatably accommodated on the end plate. The end plate itself must here be provided with apertures or gaps corresponding to the pressure pieces, the perforated plate, when the mold is opened, being rotated in such a way that the pressure pieces can pass through them, and therefore also through the end plate. The end plate of this construction is therefore weakened by a number of apertures, firstly by the central aperture accommodating the cylinder, and then by the apertures required for the passage of the pressure pieces. The pressure plate must therefore be of substantial thickness, so as to oppose the necessary resistance to bending. The production of this end plate, with the perforated disc and the pressure pieces, of which several are required, is complicated, and very expensive. A further disadvantage resides in the fact that the bridging over of the different stroke lengths given by the various molds has to be effected by the pressure box, which must be of a comparatively large volume, and therefore has the disadvantages already described above.

In yet another arrangement (DAS No. 1,147,750) the closing device is likewise accommodated in the middle of the end plate, while the cylinder carries the freely movable mold-carrier plate, the piston of the closing device is secured in the end plate, and the end plate must have a casing accormnodating the cylinder of the closing device. The adjusting of different stroke travels is effected by way of a rotatable sleeve accommodated in the end plate, by means of which the casing of the closing cylinder is adjusted in an axial direction. In this construction the design or construction of the end plate is again very complicated, making this end plate very expensive to manufacture. On the end face of the end plate, with this structure, at least two diametrically opposite sliders are arranged, which, when the mold is closed, engage underneath the end of the clos-- ing cylinder, and lock the latter in its mold-closing position. Before the opening of the mold these sliders must be simultaneously retracted, in order that the closing cylinder may be able to enter its casing, accommodated in the end plate. The guides for these sliders, which serve for the locking, must be so constructed that in the locked position the slider is secured against tilting or canting.

With all these known constructions there is an additional disadvantage in that the provision of an ejector renders necessary considerable difficulties and great constructional expenditure.

OBJECT OF THE INVENTION The present invention has as its object obviating the disadvantages inherent in the known constructions, and providing a mold-closing device which is distinguished by a reliable method of working, with the lowest possible expenditure on construction, and in which the weakening of the end plate is reduced to the smallest possible extent.

SUMMARY OF THE INVENTION This is attained, according to the invention, by the fact that at least two pistonand-cylinder units are provided, which act on the stationary mold-carrier plate or on the end plate on the one hand, and on the movable mold-carrier plate on the other hand, that on the end plate is arranged a thrust plate which covers an aperture that serves for the passage of the pressure piece and which is movable perpendicularly to the movement of the mold-carrier plates, and that the pressure piece, in a manner known in itself, is constructed as a nutand-spindle unit serving for continuous longitudinal adjustment to the width of the mold.

By the co-operation, according to the invention, of the features claimed, the result is obtained that the requirements subsisting with these mold-closing devices as regards minimum weakening of the end plate and as regards simple adjustability to different strokes, are taken into account in an exemplary manner. By the arrangement, known in itself, of the closing cylinders, it is possible to arrange a pressure piece midway between the end plate and the movable mold-carrier plate, so that only an aperture corresponding to the diameter of the ram of the pressure piece is required in the closure plate. By the arrangement according to the invention of a thrust plate serving as a simple slider, the cost of production is reduced to a minimum. In addition to this, since this thrust plate can be held by means of simple guiding rails secured upon the end plate, fixing in an exact end position is not required. With the construction of the pressure piece as a nutand-spindle unit, it is ensured that a pressure box of minimum volume may be employed.

The mold-closing device according to the invention is distinguished by its simple, cheap and reliable construction, and by the fact that it renders possible a simple arrangement of the requisite ejector, without thereby increasing the dimensions of the machine.

DESCRIPTION OF THE DRAWING One embodiment of the device according to the invention is illustrated by way of example in the accompanying drawing, in which:

FIG. 1 is a side view of the mold-closing device, wherein the front closing cylinder is omitted; and

FIG. 2 shows a horizontal section of the device according to FIG. 1, wherein the struts or crossbeams are located in the plane of section.

SPECIFIC DESCRIPTION FIG. 1 shows the device with the mold opened, and FIG. 2 with the mold closed. Upon the struts or columns 1, of which four are provided, is fixedly arranged at the end a mold-carrier plate 2, which is provided with a central aperture 3 for an injection cylinder 4 and an injection nozzle 5. At the opposite end of the struts 1 there is a stationary end plate 6. Between the mold-carrier plate 2 and the end plate 6 is arranged a movable mold-carrier plate 7. For the opening and closing of this movable mold-carrier plate 7, two cylinders 8 are provided on the stationary mold-carrier plate 2, the piston rods 9 thereof being secured to the movable mold-carrier plate 7. The two halves of the mold are marked 10 and 11. On one side of the movable moldcarried plate 7 is arranged the mold half 11, and to the other side are secured two parallel stems 12, which carry an intermediate plate 13, likewise guided upon the struts 1. The structural members 7, 12 and 13 form a unit. Upon the free surface of the intermediate plate 13 is arranged the cylinder 14 of a pressure box or hydraulic intensifier having a piston 15, which carries a pressure ram, consisting of a screw-threaded sleeve 16 secured upon the piston 15, and a ram or bolt 17 engaging in the latter. Upon that surface of the end plate 6 which faces the ram 17 is mounted a thrust plate 18, which is slidable between two guide rails 19, and which can close an aperture 20 in the end plate 6. Upon the end plate 6 are arranged two bolts 21 of adjustable length, serving as ejector abutments, The intermediate plate 13 has apertures 22, through which the ejector abutments 21 can pass. Upon the side of the intermediate plate 13 remote from the pressure box 14, 15 is arranged an ejector plate 23, which overlaps the apertures 22 and carries ejector pins 24, which engage in an aperture 25 in the movable mold-carrier plate 7. As is apparent from the drawing, the total length of pressure box and pressure plate and the thickness of the, thrust plate is greater than the length of the abutments 21 as measured from the mold-facing surface of the end plate.

Upon the end plate 6 is provided a pistonandcylinder unit 26, which is attached to the thrust plate 18, and can displace the latter in the guide rails 19.

The method of operation of the apparatus according to the invention is as follows: When, according to FIG. 2, after production of a molded article with the mold halves l0 and 11 closed, these mold halves are opened to liberate the molded article, the pistonand-cylinder unit 26 is first actuated, and this draws the thrust plate 18 so far upwards in its guides 19 that the aperture 20 in the end plate 6 is uncovered.

When, by the mold-closing pistonand-cylinder units 8 and 9, the movable mold-carrier plate 7 is displaced towards the fixed end plate 6, the ram 17 passes through the aperture 20 in the end plate 6, and the two mold halves l0 and 11 are separated. In this case the ejector abutments 21 pass through the apertures 22 in the intermediate plate 13, which is moved simultaneously with the movable mold-carrier plate 7, and then displaces the ejector plate 23, with the ejector pins 24, towards the right, into the position shown in FIG. 1, so that the molded article is pushed out. When the mold is being closed again, the mold-closing pistons 9 are moved into the positions shown in FIG. 2, and the ram 17 is drawn out of the aperture 20 in the end plate 6. Then, by the actuation of the pistonand-cylinder unit 26, the thrust plate 18 is pushed in front of the aperture 20. Thereupon the pressure box 14, 15 is supplied with pressure fluid, so that the ram 17 presses firmly upon the thrust plate 18, and the requisite closing pressure is exerted by way of the intermediate plate 13 and the stems 12 upon the movable mold-carrier plate 7. After the termination of the closing pressure, the pressure box 14 is first relieved, so that the thrust plate 18 can be pulled upwards by the pistonand-cylinder unit 26, whereupon the procedure hereinbefore described is repeated.

The pressure box 14, 15 may alternatively be arranged on the end plate 6, in which case the cylinder 14 is secured upon the end plate 6, and the piston 15 carries the guide rails 19 with the thrust plate 18. The pressure piece 16, 17 is now secured to the movable moldcarrier plate 13. The pressure box 14, 15 must here be provided with an axial aperture, which corresponds to the aperture 20 in the end plate 6, in order that the pressure piece 16, 17 may be able to pass through the end plate 6, when the mold is being opened.

I claim:

1. A mold-closing device, comprising:

a stationary mold-carrier plate;

a stationary end plate spaced from said mold-carrier plate; said movable mold-carrier plate along said rails;

mold-closure means operable independently of said pressure box for shifting said movable mold-carrier plate between said positions;

a pair of variable-length adjustable ejector abutments mounted on said end plate and projecting from said surface thereof toward said mold, the effective length of said pressure box and pressure piece plus the thickness of said thrust plate being greater than the lengths of said ejector abutments measured from said surface of said end plate;

an intermediate plate disposed between said movable mold-carrier plate and said end plate, said intermediate plate being provided with said pressure box and passages registering with said abutments;

an ejector plate between said intermediate plate and said movable mold-carrier plate in the path of said abutments upon penetration thereof through said passages; and ejector pins on said ejector plate extending through said movable mold-carrier plate for dislodging a molded article therefrom.

guide rails interconnectin said plates; a movable mold-carrier p ate slidab e along said rails between said end plate and said stationary moldcarrier plate between an open-mold position and a closed-mold position, said mold-carrier plates being adapted to mount respective mold halves;

a pressure box interposed between confronting surfaces of said end plate and said movable mold-carrier plate and including a piston member and a cylinder member connected to said movable moldcarrier plate, said pressure box being energizable during introduction of material into the mold to prevent separation of said mold halves and bearing in opposite directions on said end plate and said movable mold-carrier plate, said piston member being formed with a pressure piece extending in the direction of said end plate and constituted of a nut threadedly connected with a spindle for adjusting the effective length of said pressure piece, said end plate being provided with an aperture adapted to receive said pressure piece;

a thrust plate slidable along said surface of said end plate for selective axial alignment with and disalignment from said pressure piece for alternately covering said opening completely and uncovering said opening, said thrust plate overlying said surface of said end plate and being engageable with said pressure piece in a position of said thrust plate covering said opening;

a pistonand-cylinder unit mounted upon said end plate for shifting said thrust plate transversely to the direction of said movable mold-carrier plate along said rails;

mold-closure means operable independently of said pressure box for shifting said movable mold-carrier plate between said positions;

a pair of variable-length adjustable ejector abutments mounted on said end plate and projecting from said surface thereof toward said mold, the effective length of said pressure box and pressure piece plus the thickness of said thrust plate being greater than the lengths of said ejector abutments measured from said surface of said end plate;

an intermediate plate disposed between said movable mold-carrier plate and said end plate, said intermediate plate being provided with said pressure box and passages registering with said abutments;

an ejector plate between said intermediate plate and said movable mold-carrier plate in the path of said abutments upon penetration thereof through said passages; and

ejector pins on said ejector plate extending through said movable mold-carrier plate for dislodging a molded article therefrom. 

1. A mold-closing device, comprising: a stationary mold-carrier plate; a stationary end plate spaced from said mold-carrier plate; said movable mold-carrier plate along said rails; guide rails interconnecting said plates; a movable mold-carrier plate slidable along said rails between said end plate and said stationary mold-carrier plate between an open-mold position and a closed-mold position, said moldcarrier plates being adapted to mount respective mold halves; a pressure box interposed between confronting surfaces of said end plate and said movable mold-carrier plate and including a piston member and a cylinder member connected to said movable mold-carrier plate, said pressure box being energizable during introduction of material into the mold to prevent separation of said mold halves and bearing in opposite directions on said end plate and said movable mold-carrier plate, said piston member being formed with a pressure piece extending in the direction of said end plate and constituted of a nut threadedly connected with a spindle for adjusting the effective length of said pressure piece, said end plate being provided with an aperture adapted to receive said pressure piece; a thrust plate slidable along said surface of said end plate for selective axial alignment with and disalignment from said pressure piece for alternately covering said opening completely and uncovering said opening, said thrust plate overlying said surface of said end plate and being engageable with said pressure piece in a position of said thrust plate covering said opening; a piston-and-cylinder unit mounted upon said end plate for shifting said thrust plate transversely to the direction of said movable mold-carrier plate along said rails; mold-closure means operable independently of said pressure box for shifting said movable mold-carrier plate between said positions; a pair of variable-length adjustable ejector abutments mounted on said end plate and projecting from said surface thereof toward said mold, the effective length of said pressure box and pressure piece plus the thickness of said thrust plate being greater than the lengths of said ejector abutments measured from said surface of said end plate; an intermediate plate disposed between said movable mold-carrier plate and said end plate, said intermediate plate being provided with said pressure box and passages registering with said abutments; an ejector plate between said intermediate plate and said movable mold-carrier plate in the path of said abutments upon penetration thereof through said passages; and ejector pins on said ejector plate extending through said movable mold-carrier plate for dislodging a molded article therefrom. 